Acoustic Complexity Index (ACI)

AUS-TSW-LVG-ACI General Low confidence

Benchmark Value

No specific value — see range
Range: 1650 to 1750 index
Thresholds: Lower: 1450, Upper: —
Optimal Range: 1650 to 1750
Direction: Higher is desirable ↑
Form: OptimalRange

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context.

Evidence & Context

The benchmark for "best available condition" in a temperate semi-arid grazing system is derived from the ACI values recorded in the "mid-dense open forest" during the spring dawn chorus, yielding a provisional benchmark range of 1650 - 1750.

Metric Definition:

Acoustic Complexity Index (ACI) is a mathematical algorithm that summarizes audio data into a numerical value representing the complexity of biotic sounds in a soundscape.

Benchmark Definition:

ACI measures the temporal variability and complexity of biophony, reflecting the acoustic complexity of the ecosystem in temperate semi-arid grazing woodlands.

Justification:

The benchmark is derived from a proxy study in a structurally complex Australian open forest, representing an aspirational target for best available condition in a regeneratively managed semi-arid grazing landscape. Confidence is low due to proxy nature and absence of direct field data.

Sources (1)

Preview of USING ECOACOUSTIC MONITORING OF BIODIVERSITY TO INFORM URBAN DEVELOPMENT IN PERI-URBAN SETTINGS
USING ECOACOUSTIC MONITORING OF BIODIVERSITY TO INFORM URBAN DEVELOPMENT IN PERI-URBAN SETTINGS Journal

USING ECOACOUSTIC MONITORING OF BIODIVERSITY TO INFORM URBAN DEVELOPMENT IN PERI-URBAN SETTINGS

View Source

Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Preview of Plots & Transects - TERN Australia, accessed July 15, 2025
Plots & Transects - TERN Australia, accessed July 15, 2025
Contextual Support

TERN Landscapes - Terrestrial Ecosystem Research Network, accessed May 17, 2025,

View Source
Preview of This may be the author's version of a work that was submitted/accepted for publication in the following source: Fuller, Susan, - QUT ePrints, accessed August 6, 2025,
This may be the author's version of a work that was submitted/accepted for publication in the following source: Fuller, Susan, - QUT ePrints, accessed August 6, 2025,
Contextual Support Journal

Table of Contents - QUT ePrints, accessed July 17, 2025

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Context

  • Region Australia
  • Biome Temperate Semi-Arid Shrublands & Open Woodlands
  • Land Use Livestock Grazing & Pasture
  • Assessment Conservation Target
  • Vegetation Woodland
  • Season spring dawn chorus
  • Evidence Type TargetCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 18 Mar 2026

Notes

Lower Critical Threshold: 1450 - 1500 index. No upper detrimental threshold — higher values are always better up to natural saturation. RangeFixup applied 2026-03-21 22:21 UTC: LowerBound: 1650 → 1500; OptimalRangeLow: 1500 → 1650 [Migration] Original wider evidence range: 1500 – 1750 (retained OptimalRange: 1650 – 1750)